<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>GSAP Segmented Control</title>
    <style>
        .segmented-control {
            position: relative;
            display: inline-flex;
            background: #f0f0f0;
            border-radius: 8px;
            padding: 4px;
            margin: 20px;
        }

        .segmented-options {
            display: flex;
            position: relative;
            z-index: 1;
        }

        .option {
            padding: 8px 16px;
            border: none;
            background: transparent;
            cursor: pointer;
            position: relative;
            z-index: 2;
            transition: color 0.3s ease;
        }

        .option.active {
            color: white;
        }

        .indicator {
            position: absolute;
            top: 4px;
            left: 4px;
            height: calc(100% - 8px);
            border-radius: 6px;
            background: #4a90e2;
            z-index: 1;
            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.1);
        }

        .indicator.option1 {
            background: #4a90e2;
        }

        .indicator.option2 {
            background: #e24a4a;
        }

        .indicator.option3 {
            background: #4ae24a;
        }
    </style>
</head>
<body>
<div class="segmented-control">
    <div class="segmented-options">
        <button class="option active" data-value="option1">选项1</button>
        <button class="option" data-value="option2">选项2</button>
        <button class="option" data-value="option3">选项3</button>
    </div>
    <div class="indicator option1"></div>
</div>

<script src="https://cdnjs.cloudflare.com/ajax/libs/gsap/3.11.4/gsap.min.js"></script>
<script>
    class SegmentedControl {
        constructor(container) {
            this.container = container;
            this.options = Array.from(container.querySelectorAll('.option'));
            this.indicator = container.querySelector('.indicator');
            this.activeOption = container.querySelector('.option.active');
            this.resizeTimeout = null;

            this.positionIndicator();

            this.options.forEach(option => {
                option.addEventListener('click', () => this.handleOptionClick(option));
            });

            window.addEventListener('resize', () => {
                this.positionIndicator();
            });
        }

        positionIndicator() {
            if (this.resizeTimeout) clearTimeout(this.resizeTimeout);
            this.resizeTimeout = setTimeout(() => {
                const {left, width} = this.activeOption.getBoundingClientRect();
                const containerLeft = this.container.getBoundingClientRect().left;

                gsap.set(this.indicator, {
                    x: left - containerLeft - 4,
                    width: width
                });
            }, 100);
        }

        handleOptionClick(clickedOption) {
            if (clickedOption === this.activeOption) return;

            this.options.forEach(option => option.classList.remove('active'));
            clickedOption.classList.add('active');

            const {left, width} = clickedOption.getBoundingClientRect();
            const containerLeft = this.container.getBoundingClientRect().left;
            const newX = left - containerLeft - 4;

            // 高级动画效果
            gsap.to(this.indicator, {
                x: newX,
                width: width,
                scaleX: 1.1,
                duration: 0.3,
                ease: "back.out(1.7)",
                className: `indicator ${clickedOption.dataset.value}`,
                onComplete: () => {
                    gsap.to(this.indicator, {
                        scaleX: 1,
                        duration: 0.1
                    });
                }
            });

            this.activeOption = clickedOption;
        }
    }

    document.querySelectorAll('.segmented-control').forEach(control => {
        new SegmentedControl(control);
    });
</script>
</body>
</html>
